Charles f



clanch cells of the j UNITED STATESPATENT ouron.

owns 1*. BURGESS, or

' COMPANY, OF MADISON, WISCONSIN, A'CORPOBATION OF WISCONSIN.

mmuracruan or 153? CELLS.

1,305,252. 1T0 Drawing.

To all whom it may concern:

Be it known that 1, CHARLEs'F. BURGESS, a citizen of the United States, residing at Madison, in the county of Dane, State of Wisconsin, have invented certain new and the Manufacture of .and 1 do herebydeuseful Improvements in Dry Cells, (Case 111;) clare the following to exact description of the invention, such as will enable others skilled in the art to which and use thesame.

The present invention relates to Letype commonly designated as mix wherein manganese dioxid is an important element.

It is a common practice to employ manganese dioxid as one of the important ingredients of these cells, this material, often designated merely as manganese, being mixed witlrcarbonaceous material such as graphite, carbon or the like, to serve as an envelop for the carbon electrode of the cell and yielding oxygen to lessen polarization when the cell is in action. The material which has been the standard for this work has been the high grade pyrolusite ore obtained from Russia, and analyzing about 85%, MnO and less than material has usually been ground to a 2(1- mesh size, or finer, before using.

1 have found that-the ampere hour capacity of a dry cell is dependent not only on the percentage of MnO in the depolarizing material, but also upon the physical condition of-this material. A hard, dense ore gives less porous material of the same fineness, and same percentage of MnO and 1 have discovered .a method of treating manganese.

use in dry cells,.

oxid ores preparatory to whereby their efficiency as a .dry cell material is very much increased, and whereby materials which have not heretofore been regarded as suitable can be made to'give good results. V

The process of my present invention comprises an electrolytic treatment .of manganese oxid ore to convert some of its manganese dioxid to a lower oxid, and this is accompanied or followed by a treatment with a suitable solvent to dissolve out said be va full, clear, and

dry cells, and is directed more particularly to any improved (lGPOlEIHZIDg 1% of iron. This satisfactory results than a softer,

specification of Letters Patent. 7 I i Patented June 3, 1919, Application encum r/20,1917. Serial no. 197,555.

lower oxid and leave a porous residue of relatively pure manganese dioxid. The electrolytic oxid may be regarded as ajprelim'inary step and may be effected by grinding. the ore to a 20-mesh size" or" finer, intimately mixing it with a carbonaceous material, such as carbon, graphitefor a mixture of the two,

arranging the mlxso formed in contact with a carbon electrode,

in nascent condition it produces the demnmson, wisconsntinssrenoa TO nurtenss urner treatment of the manganese diand then with an 'elec- I trolyte of sal ammoniac-zinc chlorid such as sired partial, reduction of the manganese dioxid to a lower ,oxid. The mix, after treatment as above described, may then be broken up and leached with water to recover the sal 'ammoniac-zinc chlorid electrolyte, and then treated for removal of the lower oxid to leave the manganese dioxid (mixed with carbonaceous material) inn more porous condition than before the treatment.

The treatment for removal of the lower oxidmay be effected with an aqueous solvent and preferably is eflected with a dilute mineral acid, such as 10% sulfuric acid, or an equivalent solution of niter cake used, or as sulfates, 1f sulfuric acid or niter cake is used, so that on washlng and drying (NaHSOJ, or 5% hydrochloric acid. vThe the residue there is obtaineda relatively pure or high grade manganese dioxid in,- timately associated with the carbonaceous material such. as carbon or graphite. 1f impurities are present, such as arsenic, antimony, nickel, chromium, cobalt or copper, they will be removed by the solvent and their removal will increase the residue and at the same time improve its quality.

The individual grains of manganese dioxid are porous and each grain resents an enormous total area. exposed or contact with the carbonaceous material and with the electrolyte when t e mixture is assembled foruseinadryoell.'

When usi a mineral acid solution as above stated for this treatment, I find that the porosity of purification is'substantially complete after agitation with the solvent for about 1 to 8 hours. The treatment can be carried on at room temperature or can be hastened by heating. v

In following the procedure above outlined, I may start with high grade Russian manganese or with the lower grade manganese oxid ores obtainable from various domestic sources and from Brazil, Cuba and elsewhere, and under the term ores, as used herein, I mean to include manganese oxid materials recovered or obtainable as by-products in the industrial arts; but I prefer to start with manganese dioxid ores that have received the preliminary electrolytic treatment, whereby some of the manganese dioxid has been reduced to. a lower oxid through the action thereon of hydrogen. This I am able to do by making use of the materials to be found in worn out dry cells which I am able to buy at low cost from junk dealers. Such cells, when torn apart, yield a mixture of manganese dioxid and carbonaceous material wherein a suitable proportion of the manganese dioxid has been reduced toa lower oxid so that on removing and recovering theelectrolyte, and subsequent treatment with acid to dissolve out the lower oxids- (and other y l lower oxld to purlfy sald mixture and reuimpurities, if any are present), there is produced an intimate mixture of highly porous and relatively pure 'manganese "dioxid intimately associated with carbonaceous material of good quality, and this mixture when used in dry cells, gives very satisfactory results. I attribute the goodresults to the high porosity of the manganese dioxid and to the intimacy of its contact with the electrolyte, and with the carbonaceous material, but other factors may contribute to the good results actually obtained in practice.

In making dry cells out of manganese oxid ore rendered porous by electrolytic reduction and subsequent acid treatment, and

intimately mixed with carbonaceous ma-f terial, such asgraphite or carbon or a mixture of graphite and carbon, I proceed accordlng to well known methods, using an electrolyte of sal ammoniac-zin'c chlorid and assembling the mixture between the zinc and carbon electrodes of the cell according to standard practices.

, I claim:

1. The method which consists in treating I I ing the mix with a mineral acid solution to dissolve out as sulfates impurities contained in the mixture and to render the dioxid porous and the mixture suitable for use as the depolarizing mix of a dry cell.

3. The method of regenerating the partially deoxidized depolarizingmix of a worn out dry cell which consists in treating the mix with a dilute solution of sulfuric acid, to dissolve out impurities and thereby render said dioxid porous and said mixture suitable for use as the depolarizing mix of a dry cell.

4. The method which consists in subjecting a mixture of manganese dioxid and carbonaceous material to the reducing action of hydrogen until some of the dioxid is reduced to lower oxid, and dissolving out said cler it suitable for use as the depolarizing mix of a dry cell.

5. The method of regenerating the partially 'deoxi'dized'depolarizing mix of a worn out dry cell, which consists in subjecting said mix to a dilute acid and dissolving out the impurities and renderin said dioxid porous and said mixture suitable for use as a depolarizing mix, substantially as described.

CHARLES r. BURGESS. 

